Trip finger for magnetos



Oct. 30, 1923.

P. BROWN ET AL TRIP FINGER FOR MAGNBTOS Filed Dec. 28. 1922 INVENTORS M ATTORNEYS Patented Oct. 30, 1923.

1,472,546 PATENT OFFICE.

PHELPS BROWN AND 18A E. EENDRICKSON, OI SPIIII'GIIED, MACH-11am, Al- BIGNOBS 'IO W100 ELECTRIC COMPANY, OI BTBINGFIELD, IABSAOHUSETTS, A COB- PORATION OI IABSAOHUSETTS.

1'31? FINGER 10B memos.

Application med December I8, 1988. lerlal Io. 80,400.

To all whom it may concern:

Be it known that we, Pnnnrs BROWN and IRA E. HENDRICKBON, citizens of the United States, residing at Springfield, in the 5 county of Hampden and State of Massachusetts, have invented new and useful Improvements in Trip Fingers for Magnetos, of which the following is a specification.

This invention relates to improvements in trip fingers, such, for example, as those used for actuating magnetos from the reciprocating push rod of an engine, and is more particularly concerned with trip fingers which are adjustable for the purpose of varying the time of actuation of the ma eto relatively to the engine.

ile the invention, as to certain features is capable of general use as an adjustable tri finger, it is especially desirable as a tri n r for magnetos o the typp disclose in t e pendinlg a iplication for S. Letters Patent of re Hendrickson, Serial No. 504,334, filed September 30, 1921. In magnetos of this type, there is associated with the trip finger a drive spring,

which functions to move the armature rapi ly away from its poles after the magnetic hold, or other forces tending to hold the armature to its poles, have been overcome. The trip finger proper is mounted for sliding movement in its body and, when first engagin with the armature or connected parts, s ides in the body without moving the armature, which sliding movement is made use of to stress the drive spring to the desired degree for subsequent action. Eventually tri finger is arrested by an abutment on the b0 y and the armature is then initially dislodged by an inelastic transmission of force from the engine push rod, after which the drive spring comes into play and moves the dislodged armature away from its poles at a speed greater than that of the push rod.

This invention has for its ob ect to provide a trip finger for the uses above described, which is of generally simplified and improved construction and ca able of being manufactured at comparative y low cost.

Another object of the invention is to provide in a trip finger of the claw described im roved means for adjusting the latter for timing pu i Another ob ect of invention is to prothe sliding movement of thevide improved means for mount' the trip finger pro r in its body so that it can be convenient assembled or subsequently removed quic ly and replaced in a new position to bring new wearing surfaces into her objects and advantages will a pear in the following description and in the illustrative embodiment of the invention in the accompanying drawings, in whiich,

Fig. 1 1s a small scale side elevational view illustrative of the mounting of the trip finger on an engine and the manner in which the trip finger cooperates with th in eto to actuate the latter;

ig. 2 is a plan view of the trip finger showing the timing lever in one position;

Fig. ,3 is a side elevational view of the trip finger showing the timing lever in another position;

Fi 4 is a cross sectional view taken on the line 4-4 of Fig. 3; and

Fig. 5 is a sectional elevational view taken on the line 5-5 of Fig. 2.

Referring to these drawings;--the tri finger proper consists of a member 6, which is mounted for longitudinal slidin movement in a suitable body, such as The body is provided stem end with a hub 8 having an axial bore 9 to permit it to be pivotally or otherwise suitably connected to the push rod of the engine, as will later appear,such hub and bore having their common axis disposed substantially tram versely with respect to the direction of slidin movement of the trip fin r 6. The body 7 is furthermore provi ed with an arm 10 which extends radially from hub 8 and is provided with two laterally extending portions 11 and 12, arranged in longitudinally spaced relation and forming guides for the trip finger 6.

The latter, as shown, is made up of two parts, the forward, or magneto engaging, portion 13 being of polygonal and preferably square cross section. The other part consists of a stud 14 threaded into one end of the part 13 and havin at a distance from such end a head 15, pro erably of cylindris cal form. The magneto drive spring, heretofore alluded to, consists of a coil sprin 16 which encompasses the body portion 0 stud 14 and acts between two washers 17* and 18. The washer-s17 and 18 are loosely mounted on the body portion of stud .14 and the former bears at all times against the forward end face of the guide 11 while the latter bears at all times against the inner ehd face of the square portion 13 of the he guide 11 has a cylindrical bore to slidin ly receive the head 15 of the trip fin er and fully encompass the periphery thereo at all times durin its normal sliding movement. The ide 1 is milled out to form a slideway for t e squared portion 13 but this slideway is open at its u per end and only artially encompasses sue portion, whereby t e latter is free to be removed from the body by an upward movement, or a movement in a direction laterally with res act to that in which the trip fin r slides. onsequently, by an outward u on the trip finger in a longitudinal direction, the head 15 may be wit drawn from the encompassing confines of I glide 11 and, when thus pOSltlOnB'l, it can v sired. a screw 22 threaded into a lu log 28 and entirely removed from the body by moving it in a lateral direction. The spring 16, being nearly fully expanded when in the illustrated position, is readily compressed to a sufiicient degree to permit the action described. This spring, however, preferably exerts a slight force on the end walls of uides 11 and 12, when it is positioned as 1 lustrated, in order to frictionally hold the trip finger in position on the body. It will thus be seen t at the assembly of the trip finger in the body or its removal therefrom is a very sim le matter, which can be accomplished quic ly and with convenience. The trip finger, having as shown, four similar faces, can be removed turned to present a new working face and again replaced in a re short time.

ince the tri finger is slidingly mounted in the body, it becomes necessa to rovide an abutment, or abutments, with w ich it ma enga to limit its slidin movement an provi e for the desired ine astic transmission of force from the body to the magneto. Preferably, at least two abutments are provided in order to secure proper timing of the magneto spark for norms. engine speeds and a retarded spark for startin or low engine speeds. To this end the hu 8 is milled oil on one side to provide a square face adjacent the inner end face of guide 11. A second abutment, in the shape of a plate 21 is movably mounted on the body and can be manually interposed between the guide 11 and the abutment 20, when de- This plate 21 is pivotally mounted on 23 on the body and is conveniently movab e 'by a timing lever 24 formed as an integral part of the piste. A spring 25 coiled, about the shank 0 screw 22, acts between the head of the latter and plate 21 tqforoe the plate against time irrationally hold the latter in position. The tri finger is roperly positioned for norma engine spee s when its inner end abuts the plate 21 and, when this plate is removed from the path of the trip finger and the latter is allowed to enage the abutment 20, retarded timin is efected. Ordinarily, therefore the pliite 21 remains in interposed osition except for short intervals when t e engine is being started.

As illustrated in Fig. 5, there is a considerable space between the head 15 and plate 21 or abutment 20, which space is purposely provided to permit the spring 16 to be substantially compressed prior to the dislodgment of the armature which is effected by an inelastic transmission of force, occurring when this head abuts the plate or the abutment. This clearance s ace, while desirable for the reason outline and preferred for magnetos of the type heretofore alluded to, is not necessarily essential for all urposes and might be nearly entirely eliminated where t e spring 16 is not required to function as a driving spring for the only clearonce then necessary would be suflicient to allow the plate 21 to be interposed between head 15 and abutment 20, when desired. The trip finger has considerable utility when used in this manner and the invention in some of its aspects is to be understood to be independent of whether or not the stressing of the spring 16 for a subsequent armature driving function is utilized.

For the special use illustrated. the spring 16 is made stronger than would otherwise be necessar and the tri finger is allowed to slide su ciently to su stantially fully compress or stress the s ring.

One way of utilizing the trip finger is illustrated in Fig. 1, wherein E 1s an internal combustion engine of any suitable ty and M a magneto of the type disclosed in tli: pending application above referred to. The armature o the ma etc is mounted to slide vertically and associated therewith are means which yieldingly hold the armature in the illustrated position and which automatically restore the armature after it has been moved downwardly from such position. This downward movement is effected b the tri finger, the forward upper edge 0 which 18 arranged to engage one arm of a bell crank lever the other arm of which is attached to the armature. The trip finger is connected to the the push erably by pivotaily connectin the be y of the finger to a bracket such as which is secured to the push rod. A small springs, applied between the bracket b andthe arm portion 10 of the trip finger body, or more properly a sprin seat ortion 26 ovided thereon, yieldingly ho] s the trip nger in {he piioper position to engage the bell crank ever rod rof the engine, \pref- In ration, as the push rod r moves to the left the forward end of the trip finger eventuall engages lever l but the force which ho d the armature a in the illustrate position, are so strong that the armature 18 not immediately moved. Instead the finger slides in its body and mmpresses spring 16. The latter even when fully stressed, is not sufiiciently powerful to dislodge the armature, which operation is effected only when the fin r engages either of the abutments provide on the trip finger body and then by an inelastic transmission of force from the ush rod r. Immediately the armature a. is islodged and even a very small air ga created between the armature and its es, the armature supporting forces, which include the force of magnetic attraction, are so materially diminished by the weakening of the latter force that the a force of the stressed drive spring 16 is "driving spring on the trip fin superior to them. The drive spring accordingly relieves its stress and moves the armature away from its poles at a speed greater than that of push rod 1-. As the latter continues to move the trip finger is freed from the lever Z, as by a screw t, which, as the lever Z, turns, ushes the finger away from the lever, allowing the fin r to move to the left beyond the illustrat fposition.

An important feature 0 the trip finger consists in the means employed for varying the time of actuation of the magneto relatively to the engine. Particularly, the separation of such means from the pivotal connection is deemed desirable. Heretofore, an eccentric has been used for this purpose, such eccentric being received in a cylindrical bore of the trip finger body and forming the pivotal connection therefor. With a trip finger like the present one a substantial portion, or portions, of the eccentric surface would have to be used for abutment by the trip finger and consequently such portions would reduce the bearing surface available for the pivotal connection, especially where the eccentric is flattened somewhat on opposite sides, as is customary, to provide flat faces for abutment with the trip finger. Also the present arrangement is far cheaper to manufacture and is fully as satisfactory and efiicient as the eccentric.

The particular manner of asembling the is also considered important as well as t e arrangement whereby these assembled parts may be removed from, or replaced in the trip fin fir body quicklly and conveniently.

e invention as been disclosed herein, in an embodiment at present preferred, for illustrative purposes at the sco of the inven fiou-isdefined by the appen ed claims {other than by the foregoing description. What we claim is:

1. A device of the class described, comprising a suitable body and a trip finger,

the latter bein mounted in the former for longitudinal s lding movement, two lon itudinally spaced guides provided on t e body to receive the finger, one of said uides fully encom ssing one end of the nger, the other guide partially encompassing the finger at a distance from the first guide and permitting the finger to be disengaged therefrom in a lateral direction after it has been withdrawn from the first ide in a longitudinal direction, and yiehfh ble means tending to hold said finger against removal from its guides.

3. A device of the class described, comprising, a body and a trip finger, the former having at longitudinally spaced points thereon two aligned guides to slidably receive the trip finger, t e latter having a part of polygonal cross section and one of said guides being shaped to conform thereto and also permit removal of said part laterally therefrom, the other of said guides fully encompassing the trip finger at a distance from said part, and means yieldingly holding the fin er in said last named uide, all constructs and arranged so that t e finger may be manually withdrawn from the last named guide and when freed therefrom laterally removed from the first named guide.

4. In a device of the class described, a body provided with two longitudinally spaced guides one of which consists of a cyllndrica slideway and the other of a slideway having three fiat sides arranged in right angular relation, a trip finger having a portion of square cross section to fit in the last named guide, a cylindrical portion to fit the first named guide and a connecting portion of less diameter than the square or cylindrical portions, washers on said con-s in the last named guide, -tion to slide in the first named guide and a inga portion of square cross section'to fit acylindrical porred iced portion connecting the square and cylindrical portions; washers on said reduced portion, one adjacent said cylindrical portion and one adjacent said square portion, and a spring encom assing said reduced portion and dispose between said washers and tending to force one washer against the end face of one guide and the other washer a ainst the adjacent end face of the other guide, said reduced portion being emovably connected to one of the adjacent portions.

6. A device of the class described, comprising, abody, a trip finger slidabl mounted therein, an abutment provide on the body serving to limit the movement of the trip finger in one direction, and a spacing member mounted on the bod for movement in a direction substantial y transverse to the line of movement of the trip finger and capable of being interposed between the latter and said abutment, when desired.

7. A device of the class described, comprising, a body, a trip finger slidabl mounted therein, an abutment provide on the body serving to limit the movement of the trip finger in one direction, a sprin tending to hold said finger away from the a utment, and a spacing member mounted on the body for movement in a direction substantially transverse to the line of movement of the trip finger and capable of being interposed between the latter and said abutment, when desired.

8. A device of the class described, comprising, a body, a trip finger slidabl mounted therein, an abutment provide on the body serving to limit the movement of the trip finger in one direction, a springbtending transverse to the'line of movement of the trip finger and capable of being interposed between the latter and said abutment, when desired, and means to yieldingly hold said member in the various positions to which it may be moved.

A device of the vclass described, comprising, a body, a trip finger, iiidin means on the body supporting said nger or sliding movement an abutment provided on the body with which one end of said finger may engage, means yieldingly holdin said finger away from said abutment, an a pivoted member movable between said abutment and one end of said guiding means into the path of said end of the trip finger.

10. A device of the class described, comprising, a body having means at one end for attachment to the push rod of an engine or the like and an arm extending radially from said means, an abutment provided on the latter, a guide rovided on said arm with one end face disposed adjacent said abutment, a trip finger slidably mounted in the body and having one end slidably received insaid guide, yieldable means for holdin said end of the trip finger away from said abutment, and a late pivoted to the body and movable in t e space between said end face and abutment into the path of said end of the trip finger to arrest its movement at an earlier time than it would be arrested by said abutment.

In testimony whereof we have aflixed our signatures.

PHELPS BROWN. IRA E. HENDRIOKSON.

Certificate of Correction.

It is hereby certified that Letters Patent N 0. 1,472,546, granted October 30, 1923,

u on the application of Phelps Brown and Ira E. Hendrickson, of Springfield,

assachusetts, for an improvement in Trip Fingers for Magnetos, were erroneously issued to Wico Electric (.ompanyP as assignec of the entire interest in said invention wheneas said Letters Patenl should have been issued to the inventoi's, said a Brown and 1m E. Hendrickmn, said Hendrickson assifiior b0 W100 Electric om any, of Springfield, Massachuagztts, q Corporation of aaconform to the record of the case in the Patent Ofiice.

Signed and sealed this 4th day of December, A. D., 1923.

[am] KARL FENNING,

Acting C'rmunisn'oner of Patents. 

